Hmm, and you are running version 1.6 of Logicity?
Do you get the same behavior if you use the datediff function instead of simply subtracting the values? We have never run across this before, but people have done very similar things with Logicity and have not seen this error pop up.
I have not done too much development in 2008 yet, I still primarily work in XI. Is {Page1s.Modified} a runtime value generated automatically in 2008?
Also when using the istime function did you try to use it in an if-then-else block to verify that the result of ({Page1s.Modified}-{@created}) is a time value before evaluating it? Something like:
if istime(({Page1s.Modified}-{@created}) ) = true then
time(({Page1s.Modified}-{@created}) )
Anytime you put explicit casts like that into a function I recommend using the evaluation function first. Depending on the report structure that function may not get evaluated until later on in the report. Does it give the same error in Viewer if you skip to the last page (which would cause all of the functions to be evaluated)? I have seen an error that occurs later pop up in export because to export, it has to run the report entirely and not just the first couple pages.
Thanks!
Brian